Water pump having a reservoir

ABSTRACT

A water pump may be provided with a pump housing and a reservoir. The reservoir may have a first portion integral with the pump housing and a second portion manufactured as a separate part. The second portion has an internal volume which is in fluid communication with the first portion. A method is disclosed in which a fluid is drawn into a pump housing and pressurized. Some of the fluid is forced past a seal and collected in a part of a reservoir coupled to the pump housing. That reservoir part is heated to evaporate the fluid.

TECHNICAL FIELD

The present disclosure relates generally to a water pump and, morespecifically, to a water pump comprising a reservoir.

BACKGROUND

Engines such as internal combustion engines comprise an engine block anda cooling circuit for cooling the engine block and the various partsincluded therein such as pistons and drive shafts. A water pump will beincluded in the cooling circuit for circulating a coolant through thecooling circuit.

A water pump will comprise a drive shaft extending through a pumphousing, which shaft is born by a bearing and sealed against the housingby a seal. At a side internal to the housing an impeller will beconnected to the shaft, whereas to the opposite side of the shaft apulley or drive wheel will be connected for driving the impeller. Whenthe engine is driven the shaft will be rotated by the pulley, forcingthe coolant through the cooling circuit by the impeller. A small amountof the coolant will be forced from the cooling circuit past the seal,lubricating the seal, bearing and shaft. To prevent the coolant frombeing spilled over the engine a weep reservoir may be provided,collecting the coolant passing the seal. An evaporation hole may beprovided, connecting the weep reservoir with the environment. Since thewater pump will be provided at a relatively hot side of the engine, thecoolant will evaporate from the weep reservoir through the evaporationhole.

In European Patent Application 1 748 193 (the “193 application) a waterpump is described having such configuration. In this known water pumpthe weep reservoir is formed in a frontal part of the water pumphousing. It has a cylindrical shape and has an open front end, closedoff by a plug. A channel extends from the area around the shaft and sealinto the reservoir for draining coolant passing the seal into thereservoir. An evaporation opening is provided above the plug, connectingthe reservoir with the environment, shielded by the pulley.

Although the reservoir of the “193 application can collect coolant to beevaporated, the volume of the reservoir is limited by the depth andcross section of the reservoir defined by the cast part. Coolantcollected in the reservoir may spill through the evaporation hole in theliquid phase, for example when the engine is moved in any direction,when the engine is tilted or when the engine is not heated properly to atemperature sufficient for evaporating the coolant at a sufficient rate.This means that coolant may leak from the reservoir in liquid form andspill onto the engine or any surrounding surface. This can lead tocorrosion and pollution or give the false impression that the water pumpor cooling circuit is not operating properly. Furthermore, in order toprovide for a reservoir large enough, the casting may be complicated andrequire a relatively large amount of metal, leading to undesirablemanufacturing costs and weight and a large overall size of the pumphousing. Moreover, for different engines a different size of weepreservoir may be required, leading to a number of pump housings,identical except for the size of the weep reservoir.

The disclosed water pump is directed to address at least one of theproblems set forth above.

SUMMARY OF THE INVENTION

In one aspect, the disclosure is directed to a water pump. The waterpump includes a pump housing and a reservoir. A first portion of thereservoir can be provided in the pump housing. A second portion of thereservoir is made as a separate part. The second portion has an internalvolume that is in fluid communication with the first portion.

In another aspect, the present disclosure is directed to a set of a pumphousing and a reservoir part. The pump housing comprises a first portionof a reservoir. The reservoir part forms a second portion of thereservoir and is made as a separate part from the pump housing and hasan internal volume.

In still another aspect, the present disclosure is directed to a methodof pumping fluid. The method includes drawing a fluid into a pumphousing and pressurizing the fluid in the housing. At least part of thefluid is directed to a seal and bearing, whereby at least part of thefluid is forced past the seal. At least part of that fluid is collectedin part of a reservoir coupled to the pump housing. At least the part ofthe reservoir in which the fluid is collected is heated and the fluidcollected therein is evaporated.

Other features and aspects of this disclosure will be apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal elevation view of a water pump;

FIG. 2 is a cross sectional view of the water pump of FIG. 1 taken alongthe line A-A;

FIG. 3 is a cross sectional view of the water pump of FIG. 1 taken alongthe line B-B; and

FIG. 4 is a side view, partially in cross section, of a part of a waterpump weep reservoir that can be used in a water pump of FIG. 1.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an exemplary embodiment of the currentdisclosure shows a water pump 1 attached to the frontal side 2 of anengine block 3, only part of which is shown. The engine block can be ofan engine of any type, such as en internal combustion engine running onfor example gas, diesel, natural gas, kerosene or bio fuel. In thisdisclosure reference will be made to a water pump 1 although otherliquids and mixtures than water can and normally may be pumped with thewater pump, such as but not limited to glycol and glycol solutions andother commonly available coolant fluids. The water pump 1 has a pumphousing 4 which can be cast from metal such as iron, aluminum, magnesiumor steel or alloys thereof. The pump housing 4 is provided with a numberof openings 5 through which it can be bolted to the engine block 3. Acover 6 is provided on the pump housing 4, closing an open side 7 of thepump housing 4. At least one opening 8 is provided in the pump housing 4allowing fluid communication between part of a coolant circuit 9 in theengine block 3 and an inner volume 10 of the pump housing 4.

At a side 11 of the pump housing 4 a bearing housing 12 is provided. Ashaft 13 extends through the bearing housing 12 and is born in thebearing housing 12 by a bearing assembly 14. A primary seal assembly orseal 15 is provided in the pump housing 4, sealing at one side againstthe shaft 13 and at the opposite side against the pump housing 4. Theseal 15 is provided between the inner volume 10 and the bearing assembly14. At the side of the bearing assembly 14 facing away from the seal 15a toothed wheel 16 is provided on the shaft 13. The toothed wheel 16 isor can be brought into engagement with a drive mechanism (not shown) forrotating the shaft 13. In an embodiment the drive mechanism can comprisea shaft such as but not limited by a cam shaft, crank shaft or anauxiliary shaft, having a toothed wheel engaging the toothed wheel 16.In another embodiment a drive wheel such as a pulley can be attached tothe shaft 13 at an end facing away from the engine block 3, outside thepump housing 4, for driving the pump 1 for example by a belt which beltcan in an embodiment be driven by a pulley attached to a shaft such as acrank shaft of the engine 3. In an embodiment such belt can also drive adynamo. Within the inner volume 10 of the pump housing 4 an impeller 17is mounted to the shaft 13. The impeller 17 is enclosed in a pumpchamber 18 in the pump housing 4. An inlet 19 is provided in the pumphousing 4, in fluid communication with the pump chamber 18. The opening8 opens into the pump chamber 18.

FIG. 3 shows a cross sectional view taken along the line B-B in FIG. 1.FIG. 3 shows a channel 20 extending through the pump housing 4, betweenan inlet end 21 communicating with a space 22 between the bearingassembly 14 and the seal 15 and an outlet end 23 in fluid communicationwith a reservoir, generally indicated with reference sign 24. Thereservoir has a first portion 25 incorporated in the pump housing 4. Thefirst portion 25 may be integrally cast with the pump housing 4.Alternatively at least part of the first portion 25 can be drilled orotherwise machined into the pump housing 4. The first portion 25 mayhave an internal volume V1. In the embodiment shown in FIGS. 2 and 3 thefirst portion 25 includes a substantially cylindrical bore 26 having aside wall 27 and a top face 28. The outlet end 22 of the channel 20 ispositioned in the top face 28. At the side opposite the top face 28 thefirst portion 25 has an opening 29 and has a rim portion 30, widenedrelative to the further part of the bore. A second portion 31 of thereservoir 24 is connected to the pump housing 4, in fluid communicationwith the first portion 25. In the embodiment shown the second portioncan be press fit into the rim portion 30, or it can be otherwise fixedto the pump housing 4, for example by glue, sealant, screw threat,bayonet means or any other suitable coupling. The second portion 31 hasan internal volume V2.

The second portion 31 is a part made separate from the pump housing 4.The second portion may for example be made at least partly of sheetmetal or plastic, using any appropriate technique, such as but notlimited to forging, milling, molding, casting or pressing. In FIG. 4 anexemplary embodiment of a second portion 31 is shown, in an enlargedscale, partly broken away. The second portion 31 is in this embodimentsubstantially cup shaped and can have a substantially cylindrical wall32, closed off at one end 33 by an end wall 34 and open at the oppositeend 35. The second portion can have an inner diameter D1 similar orabout equal to an inner diameter D2 of the first portion 25 above therim portion 30. The wall 32 can have a relatively small thickness W1,for example compared to the average thickness W2 of the wall 27 of thefirst portion 25 in the pump housing 4. The rim portion 31 can have aninner diameter D3 which is comparable to the outer diameter D4 of thesecond portion, at least near the open end 35, such that the innersurface 36 of the second portion can be substantially flush with theinner surface 37 of the first portion 25 between the rim portion 31 andthe top face 28. The second portion 31 has an inner length L1 betweenthe open end 35 and the end wall 34. At a distance H1 from the open end35 an outward extending rim 38 is provided on the second portion 31, inthe embodiment shown this rim can be formed by a deformation of the wall27 outward. The rim portion 30 has a height H2 similar to and preferablyequal to the height H1, such that when the second portion 31 is insertedinto the rim portion 30 the open end 35 abuts a shoulder 39 formed atthe end of the rim portion 30 and the rim 38 abuts the edge 40 of therim portion 30 at the open side of the first portion. In the embodimentshown a sealant such as a glue can be provided between the inner sidewall 41 of the rim portion 30 and the outside of the wall 27 between theopen end 35 and the rim 38. In such embodiment the rim portion 30 canform a first coupling 42 and the wall part 43 of the second portion 31between the rim 38 and the open end 35 can form a second coupling 44.

A channel 45 extends between an inlet end 46 at the reservoir 24 and anoutlet end 47 in a surface of the pump housing 4. The outlet end 47 canform or be in communication with an evaporation opening 48. In thedetail shown in FIG. 3 the outlet end 47 is positioned in a recess 49 inthe face 50 of the pump housing 4 behind the cover 6. The recess 49opens to a side 51 of the pump housing 4 and defines the evaporationopening 48. The channel 45 can have a longitudinal axis 52 extending atan angle α relative to a longitudinal axis 53 of the first portion 25.The angle α is preferably such that the channel 45 runs slightly upwardin the direction of the outlet end 47 and can for example be betweenabout 90 and 110 degrees. The inlet end 46 of the channel 45 can beclose to or even directly adjacent to the top face 28. Alternatively theinlet opening 46 can be in the top face 28. In general the inlet openingcan be above the lower most part of the reservoir 24, preferably abovethe end wall 35 of the second portion 31 and more preferably above thesecond portion 31.

As is shown in FIG. 2 a ventilation channel 54 can be provided at anupper part of the pump housing 4, connecting the space 22 with theenvironment 55 of the pump housing. Ventilation channel 54 can extendsubstantially vertically from the space 22 to a top 56 of the pumphousing 4 and can extend as a tangent of the space 22.

The inner volume V1 of the first portion 25 can for example be betweenabout 0 and 12 cubic centimeter (cc), preferably between about 0 and 6cc. In a preferred embodiment the first volume V1 can be between about 2and 5 cc. The second volume V2 can for example be between about 1 and 12cc, preferably between about 1 and 10 cc, more preferably between about1 and 8 cc. In a preferred embodiment the second volume V2 can bebetween about 2 and 5 cc. The total volume V of the reservoir 24 can forexample be between about 5 and 20 cc, preferably between about 6 and 15cc. In a preferred embodiment the volume V can be between about 7 and 14cc. The internal volume V1 of the first portion can be defined by thevolume enclosed within the part of the wall 27 extending between the topface 28 and the shoulder 39. The internal volume V2 of the secondportion 25 can then be defined by the volume enclosed within the outerwall thereof. In this disclosure the word about has to be understood asmeaning that at least a deviation of 10% of any given value is alsodisclosed, unless specifically indicated otherwise.

With a pump housing 4 of a given configuration, for example as shown inFIG. 1-3, different second portions 31 can be used, as long as they havea second coupling 44 that can be coupled with the first coupling 43 ofthe first portion 25. This means that different second portions 25having different internal volumes V2 can be used with the pump housing 4for providing reservoirs 24 having different volumes V, shapes and/ordimensions. Furthermore, second portions 25 made of different materialsand/or using different techniques can be used. Any one of the secondportions 25 and a pump housing 4 can form a set 57 allowing theformation of a reservoir with a specific size and configuration,suitable to for example a specific engine or use.

In an embodiment the volume V of the reservoir can be almost entirelyformed by the volume V2 of the second portion 25. The rim portion 30will then be directly adjacent the top face 28.

In a further embodiment the reservoir may have a longitudinal axis 34extending substantially parallel to the shaft 13, providing for easycasting. In an embodiment the first and/or second portion can be nonsymmetrical or non cylindrical, or can for example be somewhat bottleshaped, having a neck portion formed by the second coupling 44 and awider body, formed by the portion between the coupling 44 and the endwall 34, which can provide for a larger volume V with a shorter overalllength L1.

INDUSTRIAL APPLICABILITY

During operation of the water pump 1 the shaft 13 is driven rotatingwithin the bearing 15. This may be effected by a gearing between arotating shaft (not shown) of the engine 3 and the toothed wheel 16. Theshaft 13 rotates the impeller 17 in the pump chamber 18, which is atleast partly filled with coolant. By the rotation of the impeller 17coolant is drawn into the pump chamber 18 from the coolant circuit 9,through the inlet 19, and is pressurized in the chamber 18. Most of thepressurized coolant may then be forced out of the chamber 18 by theimpeller 17. Part of the coolant is forced past the seal 15 into thespace 22 between the bearing assembly 14 and the seal 15, lubricatingthe seal 15, the bearing assembly 14 and the shaft 13 at least to someextend. The coolant that has passed the seal 15 and entered the space 22can be drained from the space 22 through the channel 20 and be collectedin the reservoir 24. This prevents the coolant to be spilled directly onthe engine or into the environment, preventing corrosion or pollutionand preventing an unfounded belief that the engine, especially the waterpump 1 would be leaking. This could stop for example unnecessarystopping of the engine and thus loss of operation time, undue repair orreplacement of the water pump and general annoyance for the users.Moreover, if coolant were spilled in liquid form it could also lead tointerference with for example engine management, which could also leadto for example loss of operation time and avoidable repairs and costs.

In an exemplary embodiment as shown in the drawings, coolant that haspassed the seal 15 and is collected in the reservoir 24 will for themost part be collected in the lower part of the reservoir, which isformed by the second portion 31. Since the reservoir 24 can be mainlypositioned near a front end of the engine or at least near the engine ata relatively hot position when the engine is running, heat from theengine 3 will heat up the reservoir 24 and the coolant collectedtherein. This coolant can therefore evaporate and escape from thereservoir in gaseous phase, through the channel 45 and the evaporationopening 48, passing the recess 48.

In an embodiment the second portion 31 can have a heat capacitysubstantially lower than the first portion 25. This can lead to theeffect that even at relatively low engine temperatures the secondportion 31 can be heated enough to make the coolant collected thereinevaporate.

A water pump 1 according to this disclosure can be used with any type ofengine and in any type of vehicle or machine. It has been recognizedthat some engines, vehicles or machines desire a larger reservoir thenother engines, vehicles or machines. For example, when a machine orvehicle is used on terrain leading to large elevations or on roughsurfaces or even at accelerations of decelerations of the engine, asmaller reservoir of the prior art may lead to spilling of liquidcoolant through an evaporation opening. Even if the volume of this priorart reservoir would be sufficient to hold all coolant collected thereinwhen the engine would be stationary. Increasing the overall size andvolume of such known reservoir integrated in the pump housing mightsolve such problem to some limited extend, but would lead to anunnecessarily large, expensive and heavy water pump, which would be hardto manufacture, if at all possible.

Embodiments of a water pump 1 according to this disclosure can bemanufactured by any method of manufacturing, for example casting a pumphousing 4 which includes the first portion 25 of the reservoir 24 as anintegral part. The first portion 25 can be relatively shallow, whichenables easy and secure, exact manufacturing. The first portion 25 canmoreover be relatively small in diameter, allowing positioning thereofin a part of the pump housing 4 being relatively narrow in width.Nevertheless the overall volume V of the reservoir can be maderelatively large, using a second portion 31. Furthermore, a set 57 of apump housing 4 and a second portion 31 can be chosen on the basis of forexample the intended use of the water pump and of the vehicle or machinein which an engine 3 has to be used bearing the water pump 1. Forexample when it is expected that the engine or a vehicle or machineequipped therewith will be used on rough terrain or at steep elevationsa second portion 31 can be chosen having a relatively large volume V2,resulting in a large overall volume. If the same or another type ofengine, machine or vehicle will normally be used on a smooth surface orstationary, without any significant elevation, a smaller second portion31 may be sufficient, reducing the overall volume, weight and cost ofsuch water pump 1.

Although the preferred embodiments of this invention have been describedherein, improvements and modifications may be incorporated withoutdeparting from the scope of the following claims.

1. A water pump, comprising: a pump housing; and a reservoir havingfirst and second portions, the first portion of the reservoir beingprovided in the pump housing and the second portion of the reservoirbeing a separate part having an internal volume in fluid communicationwith the first portion.
 2. The water pump of claim 1, wherein the firstportion is cast with the pump housing.
 3. The water pump of claim 2,wherein the second portion is made of at least one of sheet metal andplastic.
 4. The water pump of claim 3, wherein the first portionincludes an opening and a first coupling and the second portion isprovided with a second coupling that cooperates with the first couplingand that retains the second portion in position at the opening.
 5. Thewater pump of claim 4, wherein the first and second couplings aredesigned for at least one of a press fit connection and a sealantconnection.
 6. The water pump of claim 5, wherein the second portion ismanufactured by forging.
 7. The water pump of claim 5, wherein thesecond portion is manufactured by molding.
 8. The water pump of claim 7,wherein the first portion has a first volume and the second portion hasa second volume.
 9. The water pump of claim 8, further including anevaporation opening provided at a level above a lower end of the secondportion, preferably above the second portion.
 10. The water of claim 9,wherein the first portion has an internal volume between about 0 and 12cc, preferably between about 0 and 6 cc and more preferably between 2and 5 cc.
 11. The water pump of claim 10, wherein the internal volume ofthe reservoir is between about 5 and 20 cc, preferably between about 6and 15 cc and more preferably between 7 and 14 cc.
 12. The water pump ofany one of claim 11, wherein the second portion has a lower heatcapacity than the pump housing.
 13. A set of a water pump housingcomprising a first portion of a water pump reservoir and at least onesecond portion of the water pump reservoir made as a separate part. 14.The set of claim 13, wherein the pump housing is a cast housing and thesecond portion is made of at least one of sheet metal and plastic. 15.The set of claim 14, wherein a number of second portions is provided,the second portions having different internal volumes.
 16. A method ofpumping fluid, comprising: drawing in fluid into a pump housing;pressurizing the fluid; directing at least part of the fluid past aseal; collecting at least part of the fluid passing the seal in a partof a reservoir coupled to the pump housing; heating the part of thereservoir and evaporating the collected fluid.
 17. The method of claim16, wherein the collected fluid is heated in the part of the reservoirmade of at least one of sheet metal and plastic having a heat capacitylower than the pump housing.
 18. Engine, comprising; a coolant circuit;a water pump included in the coolant circuit, wherein the water pumpcomprises: a pump housing; and a reservoir; wherein the reservoircomprises a part separate from the pump housing and in fluidcommunication with the housing; the separate part having an internalvolume in fluid communication with the pump housing; and the pumphousing having at least one evaporation opening in fluid communicationwith the reservoir.
 19. The engine of claim 18, wherein the at least oneevaporation opening is provided at a side of the pump housing facingaway from the coolant circuit.